SK284771B6 - Toothbrush and the process for its manufacture and method for producing bristles for such a toothbrush - Google Patents

Abstract

A toothbrush comprising a brush head (30) and plastic bristle (1), possibly in bundles, which are fitted thereto, the lateral faces of some of which bristles at least carry a profile. In order to obtain an increased brushing and massage effect without changing the resistance of the bristles (1), they are given a spiral profile (5, 6). The bristles (1) can comprise a core (2) and at least one spiral (5, 6) running up the lateral faces. To make such a toothbrush, a profiled single thread (9) or a thread with grooves (11, 12) running parallel to its axis can be extruded and then twisted, the twist then being fixed. It is also possible to co-extrude a single plastic thread (9) with ribs of some plastic material having different properties running along its lateral faces and then to twist the bonded plastics and fix the twist.

Description

Technical field

BACKGROUND OF THE INVENTION The present invention relates to a toothbrush with a head on which plastic bristles, optionally bundled in bundles, are attached, wherein at least some of the bristles have a helical-shaped profile formed by twisting the profiled bristle monofilament. The invention also relates to a method of making a toothbrush and to a method of making a plastic bristle for a toothbrush.

BACKGROUND OF THE INVENTION

Toothbrushes, both hand brushes and electric toothbrushes, are generally made of extruded monofilaments with a circular cross-section. Other cross-sections have already been proposed. The cleaning effect of such toothbrushes, as well as the desired massage effect on the gums, is caused exclusively by the rounded ends of the bristles, so that the gums are not injured and receded. The bristle ends are thus to meet two contradictory requirements, i. j. on the one hand, to exert a sufficient cleaning effect on the tooth, and on the other, to exert a massage effect on the gum to prevent it from receding. The primary cleaning effect on tooth surfaces and interdental spaces is therefore insufficient.

Therefore, attempts have also been made to use a profiled bristle sheath for the cleaning process, thereby increasing the cleaning effect. DE 31 16 189 discloses, for example, the provision of bristles with differently spaced reinforcements which form new edges. Such a bristle is difficult to produce rationally, given that bristles are normally produced by spinning or troweling. extrusion. In theory, it is possible to achieve cross-sectional changes in the extrusion direction as well as to produce a bristle by injection molding. The monofilaments produced by extrusion need to be finally refined, i. j. lengthen (prestress) and heat stabilize to achieve the flexibility and the ability to re-establish the bristle. However, such an extension would, in the case of injected or extruded bristles having spacings spaced along their length, only result in the bristle being stretched and tapered at the point of the smallest cross-section between the reinforcements, while the place of reinforcement remains unchanged. Such a bristle would be completely unsatisfactory. Even if such a bristle were able to impart the necessary properties, there would be a risk that the tooth brushing would wedge in the interdental spaces and either pull or tear from the toothbrush head when pulling, or occur in the interdental space where the gums are particularly threatened by insufficient adhesion to the dental neck, to gum injury.

In other known toothbrush embodiments (JP 03 289 906 A, JP 57-116 124 U, JP 60 -145 828 U, JP 03-87332 U), either a plurality of monofilaments are twisted together or individual monofilaments, which may themselves be profiled, e.g. have a square cross section (JP 03-289 906 A, JP 57-116 124 U), profiled by a short-circuit twist around the monofilament axis. Such a bristle, on which the preamble of claim 1 is based, should have a better cleaning effect due to its spatially curved sharp edges. Also, the profile of this bristle is generally unsuitable for the treatment of teeth and oral cavity in general, due to the number of turns and the resulting edges, which could slip and injure the gums over a relatively smooth tooth surface. A large number of turns leads to a large number of weakly flexible points which adversely affect the ability of the bristles to resurface. In addition, the molecular structure of the monofilament is adversely affected by strong twisting. Such a bristle is very easily stuck in the interdental space.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a toothbrush with profiled bristles which, with unchanged strength properties, would have an increased cleaning and massage effect and would be produced at a favorable cost.

SUMMARY OF THE INVENTION

This problem is solved and the deficiencies of known toothbrushes of this kind are largely eliminated by a toothbrush with a head on which plastic bristles are attached, possibly in bundles, at least some of the bristles having a helical-shaped profile formed by twisting the profiled bristle monofilament. according to the invention, characterized in that the bristles of the profiled monofilament consist of a core, at least one helix running along its jacket, which has three to five turns per centimeter of slit length, the helix being rounded at its top.

Such a bristle can be produced by extrusion and refinement in the same manner as conventional bristles. The bristle according to the invention has the advantage that, in addition to the free end of the bristle, the helix apex and the top of the bristle also act. its transition to the sides of the helix and the sides themselves create additional brushing edges that enhance the effect of brushing teeth and interdental space without injuring the gums. Even if such a bristle penetrates between the teeth, it will not become wedged because there are no radial constrictions. In addition, the bristle can be unscrewed during extraction so that the bristle will in no way be subjected to stress forces that would be higher than with conventional brushes. By the core, respectively. the monofilament axis, not themselves helically twisted, imparts to the bristle core common properties, i. j. the necessary flexibility and resilience. Due to the relatively steep pitch of the helix, the number of effective edges at the perimeter of the bristle is limited, so that, despite the improved cleaning effect, due to the rounded helix tips, a sufficiently gentle tooth cleaning is achieved, yet a gentle massage effect on the gums. The rounding of the helix tips is preferably formed by extruding the profiled monofilament, or also subsequently by subsequent mechanical or thermal treatment.

In one preferred embodiment, at least a portion of the bristles have a single or multi-stage helix, thereby increasing the effective area while cleaning and at the same time effecting in different directions.

For manufacturing and other reasons, it is advantageous for the helix to have a trapezoidal cross-section or a substantially trapezoidal cross-section, the helix tip preferably being flattened or rounded to avoid any sharp edges. This can be achieved already by extrusion or additionally by mechanical or thermal treatment.

Since the bristle according to the invention exerts in any case a stronger abrasive effect on the tooth enamel and gums than conventional bristles consisting essentially of cylindrical monofilaments and consequently is not suitable in toothbrushes for users with very sensitive gums or tooth necks, the helix and the core are color-coded to draw the user's attention to the properties of the brush so that the user can choose a suitable toothbrush for himself. The plastic material of the helix may be colored with pigments. Since the pigment particles may be harder than the plastic matrix, the helix itself may already have some abrasive effect by coloring alone.

Preferably, the core and the at least one helix are of different materials. Thus, it is possible to adapt at least one anvil screw according to its hardness to a particular application of a toothbrush. In this case too, the user obtains information on the properties of the toothbrush by a different color of the core and the helix. Such bristles can also be obtained in a simple manner such that the profiled monofilament has a polygonal, and preferably square, cross-section. After twisting, each edge forms one helix.

For some brushes, it is necessary that the bristles have a predetermined stiffness or elasticity. Stiffness adjustment can be achieved in one preferred embodiment of the invention such that the core consists of a core that is encased in a sheath of different material. By selecting the core and sheath materials, the stiffness and elasticity of the bristles can be influenced and altered in the desired direction on the one hand, and on the other hand their effect in brushing the teeth. The protrusions extending through the housing may be either of the same material as the housing or of a different material.

The profiled monofilament itself is preferably made of elastic plastic. As a result, the bristles made of such a bristle material can be drawn in the longitudinal direction, which is associated with a reduction in their diameter, so that the bristles can be removed more easily from this interdental space and thus the bristles do not become stuck in the interdental space. It is also possible to prevent the bristles from jamming by removing the bristles during removal.

One further advantageous embodiment is that the bristles consist of a core and at least one helix extending along its sheath. The kernel sells to the bristle the usual properties, i. j. flexibility, re-uprightness and the like.

The bristles are preferably of profiled and subsequently twisted monofilament, wherein each part of the profile which projects over a notional circular cross-section whose axis coincides with the twist axis forms a helix upon twisting.

The cleaning effect depends inter alia on the amount of twist relative to the useful length of the bristle or the bristle material, i. j. from the twist of the helix formed. The pitch of the helix has been shown to be advantageous in the range between twice the useful bristle length and the bristle diameter. Thus, along the useful length of the bristle, a helix extends along the 180 ° of the bristle circumference. However, as already indicated, the helix will usually have a smaller pitch which may approach the size of the bristle material diameter.

For practical use, it is preferred that the bristle has at least two turns per cm of its length, usually three to five turns per cm of its length.

The bristles may, if necessary, be helical only for a part of their length. In order to adapt the effect of the brush to the specified framework conditions, 'spiral' bristles can be combined and processed together with other bristles.

In order to produce a toothbrush plastic bristle in the described embodiment, it is proposed according to the invention that the profiled monofilament be extruded with at least one axis parallel to the projection, then twisted at least over a portion of its length and the twisting fixed. The actual bristles can then be made by separating the filaments.

Another variant of the method of making a plastic bristle for a toothbrush or interdental cleaner is to extrude a profiled plastic monofilament together with protrusions of plastic having other properties extending over its sheath, followed by profiling a monofilament twists at least a portion of its length and fixes the twist.

This method also allows the production of endless bristle material. Furthermore, it is possible to adapt the helix plastic to the purpose of use. For example, the core may consist of a plastic that is customary for bristles, while the helix plastic will be softer or harder or will contain abrasives. The plastic forming the helical protrusions may also have a different coloration to provide an indication of the function of the brush.

In addition, the core may also be of locally diverse materials in order to adapt the bristles to the purpose of their use. The core consists of an inner region or core and a single-extruded sheath which surrounds the inner region, which is of a different material.

The extruded profiled monofilament preferably extends before twisting.

In addition, it is preferred that the extruded profiled monofilament is thermally stabilized after twisting. It is further preferred that the twisted profiled monofilament, after heat stabilization, is stored, for example, for 24 to 48 hours, optionally at elevated temperature, to promote heat stabilization.

Another possibility is to extrude at least two monofilaments, which are then twisted together and fixed. The monofilaments can be non-detachably connected during extrusion or after twisting.

In the bristle according to the invention, it is furthermore possible that the extruded profiled monofilament or, in one operation, the extruded "composite" profiled monofilament, is extended and optionally stabilized before twisting so that the helical bristle obtains the properties required for toothbrushes.

For toothbrushes, the bristle tips must be rounded after cutting to prevent injury or damage to the teeth or gums. This is preferably done by surface melting of the bristle ends, which is carried out so that the edges of the thin-walled helices melt earlier than the core, so that the sharp edges are first rounded.

The bristles produced by the method are also suitable as interdental cleaners or interdental cleaners. Such a device also has other advantages since only a part of its length is twisted. The non-twisted portion has a smaller cross-sectional dimension and is therefore easier to insert into the interdental space. The introduction can be further facilitated by the fact that the non-twisted portion has at least part of its length a flattened cross-section formed, for example, by pressing.

In order to achieve a flawless and pull-out fastening of the bristles to the brush body, a solution is used in which the bristles are sealed individually or in bundles at the attachment end and attached thereto to the toothbrush neck. This gives the end of the attachment a regular round or oval cross-sectional shape, which allows an anchorage in the brush head to be flawless.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described in detail below with reference to the following figures, in which:

Fig. 1 shows a schematic side view of a toothbrush, FIG. 2 shows an enlarged detail of a bristle, FIG. 3 to 5 different cross sections of a profiled monofilament; and FIG. 6 to 11 different cross-sections in a single extruded profiled monofilament of at least two different materials.

DETAILED DESCRIPTION OF THE INVENTION

The toothbrush of FIG. 1 has a head 30 and a handle 31, which are connected to each other above the flexible neck 32. The head 30, handle 31 and neck 32 are generally ejected from the plastic, or the head 30 is attached to the neck 32 additionally. The bristles 1 are fastened to the head 30 in bundles 33. The bristle bundles 33 are shown only schematically and consist in each case of a plurality of plastic bristles 1, which are attached to the head 30 by welding, injection molding or mechanical means.

In FIG. 2, a single bristle 1 of bundle 33 is shown. This bristle 1 consists of a cylindrical core 2, on the sheath 3 of which in this case a thread 4 with a two-step inclination with a pair of helixes 5, 6 is arranged. rounded apex 7, respectively. Such a toothbrush bristle 1 may have an outer diameter of about 0.2 mm, the core 2 having a diameter of 0.1 to 0.15 mm. The thread 4 has a number of threads 4 of from 2 to 6 for a normal length of bristle 1 intended for a toothbrush of 1.5 cm.

The bristle 1 of FIG. 2 can be produced in different ways. It may e.g. FIG. 3, extruded a profiled monofilament 9 with a core 2 and two opposing protrusions 11, 12 which is subsequently elongated, then twisted and finally thermally fixed so that the two-stage thread 4 of FIG. 2. FIG. 4 shows an extruded profiled monofilament 9 with an approximately triangular cross-section consisting of a core 2 and three protrusions 14, 15 and 16. FIG. 5 shows a cross-sectional profiled monofilament 9, which in turn consists of a core 2 and four symmetrically arranged protrusions 18, 19, 20 and 21. The twist axis coincides with the axis 2 of the core 2 in all embodiments. The profiled monofilament 9 can also have a substantially rectangular, e.g. the cross-sectional area of the axis then represents the core 2 and the four corners are protrusions, which correspond to the protrusions 18, 19, 20 and 21 of FIG. 5. In FIG. 6 to 8 show substantially the same cross-sections as in FIG. 3 to 5, however, in this case the cylindrical cores 2 are coextruded from different materials, with protrusions 11, 12 or 14, 15, 16 or 18, 19, 20, 21 respectively. The extruded or co-extruded and in this sense "folded" profiled monofilament 9 is then lengthened, stretched, twisted, thermally stabilized and stored for one to two days.

Figures 9 to 11 show cross-sectional shapes similar to those of Figures 6 to 8, but the cores 2 have a core 10a, 13a, 17a surrounded by a shell 10b, 13b, 17b. The core 10a, 13a, 17a and the sheath 10b, 13b, 17b are of different materials. The protrusions 11, 12, or 14, 15, 16, or 18, 19, 20, 21 are of another, different material. The tube 10a, 13a, 17a, the sheath 10b, 13b, 17b and the protrusions 11, 12, or 14, 15, 16, or 18, 19, 20, 21 are simultaneously extruded in one operation and the resulting, "folded" profiled monofilament 9 is then processed as described above. The tube 10a, 13a, 17a may be of plastic typical of toothbrush bristles 1, while the plastic material of the sheath 10b, 13b, 17b and the protrusions 11, 12, or 14, 15, 16, or 18, 19, 20, 21 may be adapted to the desired cleaning or massage effects.

As shown in Figures 3 to 11 and with respect to Figure 2, the apex 7, 8 of the protrusions 11, 12, 14, 15, 16, 18, 19, 20, 21 is flattened or rounded, respectively. After separation of the bristles 1 from the endless material, the bristle ends are rounded, preferably by surface sealing, while the attachment ends of the bristles 1 are sealed individually or in bundles 33 to the head 30.

Instead of the cross-sections shown, the bristle 1 or the profiled monofilament 9 from which it is made can also have a rectangular, preferably square, cross-section. After twisting, they form the edges of such a cross-section to the protrusions. Whenever wherever reference is made to plastic, it is also to be understood as materials known as plastics.

Claims (15)

A toothbrush with a head (30) on which plastic bristles (1) are attached, possibly in bundles (33), at least some of the bristles (1) having a helical-shaped profile (5, 6) obtained on their surface by twisting the profiled monofilament (9) of the bristles (1), characterized in that the bristles (1) of the profiled monofilament (9) consist of a core (2) and at least one helix (5, 6) extending over its sheath (3) it has three to five turns per centimeter of the length of the bristle (1), the helix (5, 6) being rounded at its apex (7, 8). Toothbrush according to claim 1, characterized in that the helix (5, 6) of at least part of the bristles (1) is single and / or multi-stage. Toothbrush according to claim 1 or 2, characterized in that the helix (5, 6) has a trapezoidal cross-section. Toothbrush according to claim 1, characterized in that the helix (5, 6) and the core (2) have different colors. Toothbrush according to claim 1, characterized in that the helix (5, 6) and the core (2) are of different materials. Toothbrush according to claim 1, characterized in that the core (2) consists of a core (10a, 13a, 17a) surrounded by a sheath (10b, 13b, 17b) of different material. Toothbrush according to claim 1, characterized in that the profiled monofilament (9) is made of elastic plastic. Toothbrush according to claim 1, characterized in that the bristle (1) has a helix (5, 6) only for a part of its length. A method for producing a toothbrush plastic bristle according to any one of claims 1 to 1. 8, characterized in that the profiled monofilament (9) with at least one axially parallel projection (11, 12, 14, 15, 16, 18, 19, 20, 21) is extruded, followed by the profiled monofilament (9) at least twists on a part of its length and the twist is fixed. Method for producing a bristle according to any one of claims 4 to 8, characterized in that the profiled plastic monofilament (9) is extruded together with the protrusions (11, 12, 14, 15, 16, 18, 19, 20, 21) from the plastic. After that, the profiled monofilament (9) is twisted on at least a part of its length and the twist is fixed. Method for producing a bristle according to claim 9 or 10, characterized in that the profiled monofilament (9) extends before twisting. Method for producing a bristle according to claim 9 or 10, characterized in that the profiled monofilament (9) is thermally stabilized after twisting. A method for producing a bristle according to claim 12, characterized in that the twisted profiled monofilament (9) is stored after thermal stabilization to support this thermal stabilization. Method for producing a bristle according to claim 9 or 10, characterized in that the individual bristles (1) are rounded at their free end by a surface sealing method. Method for producing a toothbrush according to claims 1, 2 and 8, characterized in that the bristles (1) are sealed individually or in tufts (33) with their attachment ends to the head (30) and attached thereto to the neck (32). ) toothbrush.